I had an A1200 desctop with BPPC040 and it worked sortof with a converted 200W AT PSU. If the CPU load was higher than idle the mouse pointer graphic would start jumping like crasy and if I accessed both internal and external diskdrive att the same time my 3.5" HD that i had inside would spin down and upp again. I soldered a "male HD power" connector directly on the motherboard where where the powerplug is and plugged in one of the powerplugs from the PSU and it worked like a charm, guess the floppypowerplug is just as good but not as good looking.
For my BPPC I had added an extra coolingplate and fan for the 040 and cut out holes for both coolingplates in the trappdoor aswell as added feets to lift ut the computer some (fan stuck out about 1cm underneath the computer).
Now the hole lot is going into a tower though. :-D